The present invention relates to an electrical connector for printed circuit boards, and particularly to a high-speed modular connector for connecting a daughter board to a mother board.
Current electronic assembly techniques, particularly in the field of computers, utilize banks of removable printed circuit boards commonly known as daughter boards which are removably connected to associated circuitry commonly known as mother boards. Such banks of removable circuit boards require connectors with multiple rows of terminals therein, generally on 0.100 inch centers, which serve to connect traces on the daughter boards with traces on the mother boards. Typically, the traces end at rows of plated-through holes in the boards, and the boards each have a connector mounted thereon with rows of pins therein soldered to the plated-through holes. The connectors are removably matable for ready replacement of a daughter board. See, for example, U.S. Pat. No. 3,864,000. The connectors employ stamped and formed terminals which are fit into plastic housings, or the housings are injection molded onto the terminals.
In modern electronic circuits, the use of increasingly higher speed switching signals has necessitated shunting unwanted signal frequencies to ground throughout the circuitry. At the connector interfaces between mother boards and daughter boards this has been accomplished primarly by alternating ground terminals with signal terminals in the connectors in order to attenuate unwanted frequencies. This limits the number of terminals which may be used for signal transmission in a connector and thus limits the signal traces which may be interconnected. It would be most desirable to have a connector where ground means is provided in the housing so that all the terminals therein could be used for signal transmission, thus providing a high density connector.